152 



PURE CULTURES, FROM PATHOLOGIC MATERIAL 



funnel with enough sulphuric acid, considerably diluted (1 part 

 H 2 SO 4 to 9H 2 O) 1 until the fluid about reaches the constriction 

 between the two united glass globes (at M). The stopcock is then 

 closed and more dilute sulphuric acid is poured into the funnel (C), 

 where it remains as long as the cock is closed. The tube with the 

 stopcock is now connected with several Woulfe's wash bottles. This 

 is done to remove impurities from the hydrogen gas. When the latter 

 is to be generated the stopcock is opened, allowing dilute sulphuric 

 acid to run from the upper funnel into the globe which contains the 

 zinc. As soon as this takes place the development of hydrogen begins 



FIG. 75 



Kipp apparatus and accessories for generating and purifying hydrogen gas. 



and the gas escapes at the open stopcock into the wash bottles, and 

 from there into the tubes or jars which contain the media inoculated 

 with anaerobic cultures. The flow of the gas can be regulated at the 

 stopcock, which may be kept wide open or partially closed so that 

 only a moderate amount of gas escapes. When no more gas is needed, 

 all that is necessary is to close the stopcock at st. No more gas can 

 escape, hence the hydrogen accumulates in A, and presses upon the 



1 When mixing H 2 O and HjSO^ the sulphuric acid has to be poured slowly into the water. 

 It is not permissible to pour water into strong H 2 SO 4 , because the latter may become so hot 

 that dangerous consequences may be brought about. The dilute sulphuric acid must first 

 have become cool before it can be used in the Kipp apparatus. 



